In Puerto Rico, the positions are by now familiar: Protesters say a U.S. bombing range located on Vieques Island since 1941, has compromised the health of islanders. The U.S. military insists the exercises are not harmful and cannot be carried out anywhere else without compromising national security. In Vieques, two years after a stray Marine Corps bomb killed a civilian security guard, the battle lines haven’t budged.

There seemed to be some progress in 2000, when President Clinton signed an agreement allowing Navy and Marine bombing exercises to continue until 2003, but only using inert weapons and scaling back exercises whenever possible. The President also ordered a Health and Human Services analysis of the islander’s health complaints. Those results are due soon.

Puerto Rican Governor Sila Calderon repudiated the deal immediately after her election last November, but in the eyes of the Pentagon the accord remains. Thursday, U.S. District Judge Gladys Kessler bolstered the military's claim, ruling against the Puerto Rican government.

For now, the bombing range on Vieques is populated by crowds of Puerto Rican protesters and a handful of Navy pilots. Throughout the weekend and into Monday, the Navy was been forced to stop the exercises as protesters broke through barriers and formed human chains to block the entrance to the bombing range.

TIME Pentagon correspondent Mark Thompson weighs in on the Vieques standoff.

TIME.com: How hard will the military fight to keep this bombing range?

Mark Thompson: They’ll fight until their political leaders tell them to stop. The military really wants to keep using this range because it’s the only place in that part of the world where ships and planes can practice using real weapons before going off to battles.

TIME.com: Has the military considered other possible sites?

Thompson: They’ve looked at other sites in Scotland and in the Mediterranean, I think. The problem with the other possible sites is that where Vieques offers every possible training scenario, those other sites maybe offer one or two of those scenarios. So you’d have pilots having to travel to practice different maneuvers. No one site other than Vieques provides such comprehensive capabilities for training.

TIME.com: The Puerto Rican government claims the exercises and bombs have poisoned the island’s water and caused various health problems in islanders. Is the Navy at all sympathetic to these concerns?

Thompson:The Navy, of course, insists there are no health risks associated with the exercises. But it’s important, as we all know, to take the military’s health analyses with a grain of salt. Various studies have suggested they may be right  and there are still a couple of studies pending.